Michel Pastoureau’s captivating history of the world’s most popular color reveals blue’s ever-changing cultural role from prehistoric times to the modern day. Original, entertaining and enlightening, “Blue” — translated from its original French — is also beautifully illustrated. French artist Yves Klein’s “Blue Sponge Relief” is a brilliant choice for the back cover. Essentially a monochromatic work, using Klein’s patented ultramarine “International Klein Blue,” it conveys a sense of the infinite and creates a magical effect, drawing the reader into its unique and unforgettable shade, just as Pastoureau’s writing draws you into his book. One of the most surprising facts in the book is that blue does not even feature in the earliest primitive cave paintings. Reds, blacks, browns and all shades of ochre are common, but blues and greens are conspicuously absent, and the use of white is also rare. Blue also played an insignificant role in the European culture of the Middle Ages. It was not even used in painting to depict the sky, which was commonly colored white, red or gold. The Egyptians, and other peoples of Central Asia and the Middle East, however, considered blue to be a lucky color; it chased evil away and brought prosperity. Whereas the Romans believed that blue was barbaric and that bright blue eyes were ugly. Nowadays, of course, blue conjures images of the azure sky, an inviting sea, and it expresses feelings of tranquility, serenity and peace. Blue is not an aggressive color. It is reassuring and breeds hope and trust. The United Nations, UNESCO and European Union have all chosen blue for their flag. “A color is a social phenomenon,” writes Pastoureau. “It is society that ‘makes’ color, defines it, gives it its meaning.”